FirstMeaningfulPaint UMA

chrome/browser/page_load_metrics/page_load_metrics_browsertest.cc

 // Copyright (c) 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/macros.h"
 #include "base/test/histogram_tester.h"
 #include "chrome/browser/page_load_metrics/metrics_web_contents_observer.h"
 #include "chrome/browser/page_load_metrics/observers/aborts_page_load_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/observers/core_page_load_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/observers/document_write_page_load_metrics_observer.h"
@@ skipping 359 matching lines @@
     EXPECT_TRUE(content::ExecuteScript(
         browser()->tab_strip_model()->GetActiveWebContents(),
         "window.location.reload();"));
   }
 
   manager.WaitForNavigationFinished();
 
   histogram_tester_.ExpectTotalCount(
       internal::kHistogramAbortClientRedirectBeforeCommit, 1);
 }
+
+IN_PROC_BROWSER_TEST_F(MetricsWebContentsObserverBrowserTest,
+                       FirstMeaningfulPaintRecorded) {
+  ASSERT_TRUE(embedded_test_server()->Start());
+
+  ui_test_utils::NavigateToURL(browser(),
+                               embedded_test_server()->GetURL("/title1.html"));
+
+  // Wait until the renderer finishes observing layouts.
+  const int kNetworkIdleTime = 2000;
+  const int kMargin = 500;
+  const std::string javascript = base::StringPrintf(
+      "setTimeout(() => window.domAutomationController.send(true), %d)",
+      kNetworkIdleTime + kMargin);

[Kunihiko Sakamoto, 2016/08/10 02:33:32]

I noticed this test fails about once a ten times for some reasons (IPC race?) so
I had to add some margin.

+  bool result;
+  EXPECT_TRUE(content::ExecuteScriptAndExtractBool(
+      browser()->tab_strip_model()->GetActiveWebContents(),
+      javascript, &result));
+  EXPECT_TRUE(result);
+
+  NavigateToUntrackedUrl();
+  histogram_tester_.ExpectUniqueSample(
+      internal::kHistogramFirstMeaningfulPaintStatus,
+      internal::FMP_RECORDED, 1);
+  histogram_tester_.ExpectTotalCount(
+      internal::kHistogramFirstMeaningfulPaint, 1);
+  histogram_tester_.ExpectTotalCount(
+      internal::kHistogramParseStartToFirstMeaningfulPaint, 1);
+}
+
+IN_PROC_BROWSER_TEST_F(MetricsWebContentsObserverBrowserTest,
+                       FirstMeaningfulPaintNotRecorded) {
+  ASSERT_TRUE(embedded_test_server()->Start());
+
+  ui_test_utils::NavigateToURL(browser(),
+                               embedded_test_server()->GetURL("/title1.html"));
+
+  // Navigate away before a FMP is reported.
+  NavigateToUntrackedUrl();
+
+  histogram_tester_.ExpectUniqueSample(
+      internal::kHistogramFirstMeaningfulPaintStatus,
+      internal::FMP_DID_NOT_REACH_NETWORK_STABLE, 1);
+  histogram_tester_.ExpectTotalCount(
+      internal::kHistogramFirstMeaningfulPaint, 0);
+  histogram_tester_.ExpectTotalCount(
+      internal::kHistogramParseStartToFirstMeaningfulPaint, 0);
+}